Mathias Hammes - Dusseldorf / daughter Liana - Milwaukee

I am trying to trace a Liana Anna Juliana Hammes who married one of my relatives a Hugh Johnstone (Born in Scotland)in Germany in 1948.Liana and Hugh emigrated to Wisconsin in 1951 and settled in Milwaukee. I believe that Hugh and Liana seperated around 1959 Hugh and lians Johnstone were in the Milwaukee City directories up to 1958 but in 1959 Hugh appeared alone).Hugh stayed in Wisconsin but I am not sure what happened to Liana or if Huigh and Liana had any children ?

Liana was born in Germany around 1921.Her father is Mathias Hammes a Hotel keeper.At the time of her marriage Liana lived in Dusseldorf at Kaiserwerther Strasse 134.Hugh who served in the British Army and was based in Germany when they met and married.

Does anybody know of Liana or her relatives / children ? or can anybody help me with my search